Headstand assisting implement

ABSTRACT

A headstand assisting implement for assisting an intended user while the latter performs a headstand includes an implement body defining a ground contacting surface for resting on a ground surface and a substantially opposed cranium contacting surface for contacting the cranium of the intended user. The cranium contacting surface is provided with a cranium receiving concavity configured and sized for substantially fittingly receiving a predetermined portion of the cranium of the intended user so as to ergonomically support the cranium of the intended user when the intended user performs the headstand.

FIELD OF THE INVENTION

The present invention relates to the general field of implements forperforming physical exercise and is particularly concerned with aheadstand assisting implement.

BACKGROUND OF THE INVENTION

The word “yoga” is derived from the Sanskrit “yeung”, meaning to join.In Hindu philosophy, yoga is used to attain spiritual insight andharmony. In Western countries, the term yoga is often usedinterchangeably with “hatha yoga”.

The practice of “hatha yoga” involves performing various physicalpostures and relaxation exercises. The yogic physical exercises arecalled Asanas, a term which means steady pause. This is because YogaAsanas are typically meant to be held for some time. Yoga Asanastypically focus on the health of the spine, its strength andflexibility.

Although there are probably millions of Asanas, twelve selected pausesare considered as basic postures. Known as the “king of Asanas” becauseof its many benefits, the headstand is the first of the twelve basicAsanas. The headstand consists in balancing on the crown of the headalso referred to as the Sahasrara chakra.

The headstand is considered by many to be a panacea for countless humanills. Benefits of performing the headstand includes: a) reversal ofvenous flow, thus flushing out areas of stagnant or collected blood; b)reversal of the flow of cerebro-spinal fluid, resulting in formation ofnew cerebro-spinal fluid in the region of the intracerebral ventricles;c) activation of the carotid sinus barorereceptors, resulting inincreased discharge from the parasympathetic nervous system, thuslowering heart rate and blood pressure; d) strengthening of theparavertebral musculature; e) improvement of balance as a result of theestablishment of new neural circuitry by the new demand for balanceplaced on the cerebellum and vestibular apparatus; f) improvement inconcentration; g) improvement in endurance; and h) improvement inrelaxation and general well being.

Although not necessarily considered an advanced Asana, the headstandnevertheless requires some level of experience and may be potentiallyhazardous. Indeed, when performing a headstand, the cervical spine, inparticular, may be subjected to important stresses that may potentiallylead to serious injury.

Some believe that the headstand should not be performed by individualshaving cervical spondylosis, blocked arteries, osteo-arthritis of theneck or shoulders, backache, premenstrual stress or high blood pressure.Furthermore, it is typically recommended to get help from a yogapractitioner to perform the headstand in a correct and safe manner.

There exists several methods for performing a yoga headstand. Typically,the sequence is initiated by coming onto the elbows and knees about 6inches away from a wall. The hands are then placed to the outside of thetriceps muscles to establish a beginning arm position. The elbows arethen released and the fingers interlocked creating a “V” stance with theforearms. The crown of the head is then rested on the floor.

The toes are then tucked under and, while inhaling, the hips are liftedand the legs straightened. The neck must be maintained in properalignment throughout the procedure.

Once this initial position has been established, one foot is placed infront of the other, preferably the stronger leg forward. It is typicallyrecommended that most of the weight should rest on the elbows and not onthe crown of the head. However, this may actually train the bad habit ofhaving the mechanical axis of the spine anterior to the anatomic axis.

The abdominal muscles and the pelvic floor muscles are contracted and,slowly, one leg at a time, the individual floats the feet up resting thelegs on the wall. When headstand is taught in this way, the weight doesnot rest on the crown of the head, but rather rests on the elbows. It isrecommended to keep the legs together and the toes spread.

When practiced as described in the foregoing it is only when the neck isvery strong and the individual has been practicing for many years thathe or she can then place the full weight of the body on the head. As theheadstand posture is practiced, from the starting position the abdominalmuscles may be engaged first and both legs then slowly floated uptogether until in the inverted headstand position. Eventually, as theposture is established, the individual can move away from the wall andattempt it in a free-stand position. Typically, the posture is held for5 to 10 deep breaths. Many other sequences may be used to achieve aproper headstand.

Typically, most people recommend that most of the weight be distributedonto the hands and/or forearms in order to “protect” the spine. However,it is believed that by maintaining most of the weight on the forearmsand/or hands, the spine may in fact become more vulnerable since themechanical axis of the body is shifted forward of the cervical spine. Byshifting the mechanical axis away from the anatomic axis of thevertebral column, the spine and its surrounding musculature become atrisk for both acute and chronic injury. Furthermore, the advantage ofaligning the body weight with the trabeculae of the vertebral bodies,which combined with the intervertebral discs can withstand very highcompressive forces, is lost if the mechanical and anatomic axis are notaligned.

When the headstand is performed with the mechanical axis of the spinesubstantially aligned with the anatomic axis, the weight of the body isconcentrated in a small area of a part of the cranium, commonly referredto as the crown, where it is in contact with the floor. The sustentationpolygon or surface within which the centre of gravity of the body mustproject in order to maintain the body in the inverted position withoutfalling over is relatively small. Furthermore, the surface of thecranium in contact with the ground has a somewhat convex configurationwhich further reduces the overall stability of the position.

Sway or imbalance is magnified when one attempts to maintain themechanical axis and the anatomic axis concentrated in such a small area.Furthermore, in the inverted and erect position, the body becomes a longlever arm such that movements caused by relatively small forces becomemagnified. Such small forces can reach significant levels to a pointthat imbalance is created by the sway.

This sway must be countered by muscular forces in order to maintain thebody in the headstand position. These forces, in turn, can reachrelatively high levels and are transmitted in the form compensatoryflexion, extension and rotary motion at the vertebral bodies. Thesemotions and forces can result in disc bulging or herniation.

Hence, it would be desirable to provide a headstand assisting implementallowing an intended user to assume the inverted and erect positionassociated with conventional headstands wherein the mechanical andanatomic axes are in a substantially co-linear relationship relative toeach other but without the hereinabove mentioned disadvantagesassociated with such a position. In other words, it would be desirableto provide a headstand assisting implement that could allow an intendeduser to perform a headstand wherein involvement of the forearms isminimized and wherein the need for providing compensatory movements tomaintain balance is also minimized.

SUMMARY OF THE INVENTION

It is a general object of the present invention to provide a headstandassisting implement adapted to assist an intended user in ergonomicallyperforming a headstand.

In accordance with the present invention, there is provided a headstandassisting implement for assisting an intended user while the intendeduser performs a headstand, the intended user having a head including acranium, the headstand assisting implement comprising: an implementbody, the implement body defining a ground contacting surface forresting on a ground surface and a substantially opposed craniumcontacting surface for contacting the cranium of the intended user; thecranium contacting surface being provided with a cranium receivingconcavity, the cranium receiving concavity being configured and sizedfor substantially fittingly receiving a predetermined portion of thecranium of the intended user so as to ergonomically support the craniumof the intended user when the intended user performs the headstand.

Conveniently, the cranium receiving concavity has a substantially ovoidconfiguration when seen from a top view, the ovoid configuration of thecranium receiving concavity defining a concavity long axis extendingsubstantially longitudinally across the cranium receiving concavity anda substantially perpendicular concavity short axis extendingtransversally across the cranium receiving concavity, the concavity longand short axes being sized so that the outline of the cranium receivingconcavity corresponds substantially to the outline of the predeterminedportion of the cranium of the intended user.

Preferably, the cranium receiving concavity defines a concavity mainsection and a concavity auxiliary section, the concavity main sectionbeing located substantially centrally relative to the cranium receivingconcavity; the concavity auxiliary section being located peripherallyrelative to the concavity main section, the radius of curvature of theconcavity auxiliary section being greater then the radius of curvatureof the concavity main section;

In at least one embodiment of the invention, the concavity main sectionis hollow. In another embodiment of the invention, at least a portion ofthe concavity main section and the concavity auxiliary section are madeout of different materials.

Preferably, the implement body is made out of an integral piece ofsubstantially resiliently deformable body material.

Advantages of the present invention include that the proposed implementallows an intended user to perform a headstand with reduced risks ofinjury. The proposed implement is also intended to provide a greatersense of comfort, security, stability and capability to an intended userpracticing headstands.

In turn, the improved comfort, security, stability and capability enablethe body of an intended user to maintain headstands for a longer periodof time. It also enables the intended user to place the body in avariety of headstand positions.

The proposed implement is designed so as to allow the body of theintended user to maintain its mechanical axis substantially in line withthe anatomic axis during performance of the headstand.

Also, the proposed implement is designed so as to act as an interfacebetween the crown of the head of the intended user and the groundsurface and to provide an enlarged contact surface with the groundsurface.

Still furthermore, the proposed implement is designed so as to provideself-alignment features adapted to reduce the need for the intended userto exert muscular tension in an attempt to maintain balance. In otherwords, the proposed implement is designed so as to improve the stabilityof the intended user when the latter is in the headstand position.

Also, the proposed implement is designed so as to be usable by a widerange of users having a relatively wide range of anthropometric valuesin terms of head size and configuration.

Yet, still furthermore, the proposed implement is designed so as to bemanufacturable using conventional forms of manufacturing andconventional materials so as to provide an implement that willeconomically feasible, long-lasting and relatively trouble-free inoperation.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present invention will now be disclosed, byway of example, in reference to the following drawings in which:

FIG. 1, in a perspective view, illustrates a headstand assistingimplement in accordance with an embodiment of the present invention;

FIG. 2, in a top view, illustrates the headstand assisting implementshown in FIG. 1;

FIG. 3, in a partial perspective view with sections taken out,illustrates some of the features of the headstand assisting implementshown in FIGS. 1 and 2;

FIG. 4, in a longitudinal cross-sectional view taken along arrows IV-IVof FIG. 2, illustrates some of the features of the headstand assistingimplement shown in FIGS. 1 through 3;

FIG. 5, in a longitudinal cross-sectional view similar to that of FIG.4, illustrates a headstand assisting implement in accordance with asecond embodiment of the present invention;

FIG. 6, in a longitudinal cross-sectional view similar to that of FIGS.4 and 5, illustrates a headstand assisting implement in accordance witha third embodiment of the present invention;

FIG. 7, in a transversal cross-sectional view, illustrates a headstandassisting implement in accordance with an embodiment of the presentinvention, the headstand assisting implement being shown used by anintended user in the headstand position, the intended user being shownin phantom lines and part of the vertebral column of the intended userbeing shown in full lines;

FIG. 8, in a transversal cross-sectional view, illustrates a headstandassisting implement in accordance with an embodiment of the presentinvention, the headstand assisting implement being shown with the headof an intended user resting thereon, the head being shown in phantomlines and in an angular offset relationship relative to a vertical axis,part of the cervical spine of the intended user being shown in fulllines.

DETAILED DESCRIPTION

Referring to FIG. 7, there is shown, in a transversal cross-sectionalview, a headstand assisting implement in accordance with an embodimentof the present invention generally indicated by the reference numeral10. The implement 10 is shown being used by an intended user 12performing a headstand.

The intended user 12 has a head 14 supported by a neck 16 extending froma torso 18. The intended user 12 also has a pair of arms includingforearms 20 and a pair of legs 22 extending from the torso 18.

In FIG. 7, the intended user 12 is shown performing a typical yogicposture or Asana wherein the legs 22 are crossed and wherein the back ofthe head 14 is placed in the hollow of the palm (not shown). It should,however, be understood that the implement 10 could be used forperforming other types of headstands without departing from the scope ofthe present invention. Furthermore, although the implement 10 wasprimarily designed for use in practicing yoga or the like, it should beunderstood that the implement 10 could be used in other contexts and forpracticing other types of activities such as gymnastics, generalphysical conditioning or the like without departing from the scope ofthe present invention.

The head 14 of the intended user 12 includes a cranium. As is well knownin the art, when seen from the top, the human cranium typically has asubstantially ovoid or egg-shaped outline or configuration. When seenfrom the front or the rear, the top portion or crown 24 of the humancranium typically has a substantially rounded and convex configurationor outline. Although FIGS. 7 and 8 illustrate a cranium having a crownportion 24 with specific anthropometric parameters, it should beunderstood that the implement 10 is intended to be used by individualshaving a variety of cranium anthropometric parameters without departingfrom the scope of the present invention.

FIGS. 7 and 8 also schematically illustrate part of the vertebral column26 of the intended user 12. As is well known in the art, the vertebralcolumn includes vertebrae 28 and intervertebral discs 30 positionedtherebetween.

The headstand assisting implement 10 includes an implement body 32. Theimplement body 32 defines a crown contacting surface 34 for resting on aground surface 36. The implement body 32 also defines a substantiallyopposed cranium contacting surface 38 for contacting the cranium of theintended user 12.

As illustrated more specifically in FIGS. 4, 5 and 6, the craniumcontacting surface 38 is provided with a cranium contacting concavity40. The cranium receiving concavity 40 is configured and sized forsubstantially fittingly receiving a predetermined portion of the craniumof the intended user 12 so as to ergonomically support the cranium ofthe intended user 12 when the latter performs a headstand.

As illustrated more specifically in FIG. 2, the cranium receivingconcavity 40 has a substantially ovoid configuration when seen from atop view. The ovoid configuration of the cranium receiving concavity 40defines a concavity long axis 42 extending substantially longitudinallyacross the cranium receiving concavity 40. The ovoid configuration ofthe cranium receiving concavity 40 also defines a substantiallyperpendicular concavity short axis 44 extending transversely across thecranium receiving concavity 40. The concavity long and short axes 42, 44are sized so that the outline of the cranium receiving concavity 40corresponds substantially to the outline of the predetermined portion ofthe cranium of the intended user 12.

Typically, the cranium receiving concavity 40 is configured and sizedfor substantially fittingly receiving the so-called crown portion 24 ofthe cranium of the intended user 12. Preferably, the crown portion 24intended to contact the cranium receiving concavity 40 is defined asextending between the two parietal bones and the posterior portion ofthe frontal bone, the center of the cranium receiving portion being thenative fontanelle.

The cranium receiving concavity 40 is configured and sized forsubstantially fittingly accommodating the crown portion of an intendeduser having anthropometric parameters located between that of the 5^(th)and 95^(th) percentile of human craniums. Typically, the concavity longaxis 42 has a value of approximately between 12.5 centimetres and 14centimetres and the concavity short axis 44 has a value of approximatelybetween 10 centimetres and 11.2 centimetres.

As illustrated more specifically in FIGS. 4 through 6, the craniumreceiving concavity 40 typically has a substantially flattened parabolicconfiguration when seen in a longitudinal cross-section taken about theoval long axis 42. Typically, the profile of the surface of the craniumreceiving concavity along the concavity short axis 44 also has asubstantially parabolic configuration.

As illustrated more specifically in FIGS. 1 and 2, the cranium receivingconcavity 40 defines a concavity main section 46 and a concavityauxiliary section 48. The concavity main section 46 is typically locatedsubstantially centrally relative to the cranium receiving concavity 40while the concavity auxiliary section 48 is typically locatedperipherally relative to the concavity main section 46.

As illustrated more specifically in FIGS. 4 through 6, the radius ofcurvature of the concavity auxiliary section 48 is greater than theradius of curvature of the concavity main section 46. The concavity mainsection 46 defines a main section radius of curvature 50 while theconcavity of the auxiliary section 48 defines an auxiliary sectionradius of curvature 52. Typically, the main section radius of curvaturehas a value of approximately between 20 cm and 22 cm while the concavityof the auxiliary section radius of curvature 52 has a value ofapproximately between 36 cm and 51 cm.

As seen more specifically in FIG. 2, the concavity main section 46 alsohas a substantially ovoid configuration. The ovoid configuration of theconcavity main section 46 defines a main section long axis extendingsubstantially longitudinally across the concavity main section 46 and asubstantially perpendicular main section short axis extendingsubstantially transversely across the concavity main section 46.Typically, the main section long axis has a value of approximatelybetween 6.25 centimetres and 7 centimetres while the main section shortaxis has a value of approximately between 5 centimetres and 5.6centimetres.

The cranium receiving cavity 40 defines a concavity peripheral edge 54.As illustrated more specifically in FIG. 4, the level difference betweenthe concavity peripheral edge 54 and the nadir of the cranium receivingconcavity 40 defines a concavity depth 56. Typically, the concavitydepth 56 has a value between 1.6 centimetres and 1.8 centimetres.

The distance between the nadir of the cranium receiving concavity 40 andthe ground contacting surface 34 defines a body minimal thickness 58.Typically, the body minimal thickness 58 has a value of approximatelybetween 0.635 centimetres and 1.0 centimetre.

Typically, the concavity peripheral edge 54 has a substantially roundedconfiguration or contour. The concavity peripheral edge 54 hence definesa corresponding peripheral edge radius of curvature 60. The peripheraledge radius of curvature 60 typically has a value of approximatelybetween 0.3 centimetres and 0.5 centimetres.

The implement body 32 includes a body peripheral surface 62 extendingbetween the concavity peripheral edge 54 and the ground contactingsurface 34. The body peripheral surface 62 tapers generally inwardly ina direction leading from the ground contacting surface 34 to theconcavity peripheral edge 54.

The body peripheral surface 62 extends at a peripheral-to-groundcontacting surface angle 64 relative to said ground contacting surface34. Typically, the peripheral-to-ground contacting surface angle 64 hasa value of approximately between 65 degrees and 90 degrees.

The implement body 32 is preferably made out of an integral piece of asubstantially resiliently deformable body material. Typically the bodymaterial is a polymeric or elastomeric resin. Typically, the bodymaterial is a Urethane polymer sold under the Trademark Gel or Evergreen#10-A (non toxic) or other substantially similar suitable material.Typically, the body material provides substantially the followingcharacteristics: a viscosity of approximately 600 PCS, an elongation ofapproximately 1.000%, a tensile strength of approximately: 200 PSI and atear of approximately PLI 25 PI.

As illustrated more specifically in FIGS. 3 through 6, at least thecranium receiving concavity 40 and typically both the cranium receivingconcavity 40 and the body peripheral surface 62 are coated with acoating material having a coating material friction co-efficient equalto or lower then that of Lycra (a trademark). Typically, the coatingmaterial is a coating layer or film 66 of Lycra or similar materialadhesively or otherwise secured to the implement body 32.

In use, as illustrated in FIGS. 7 and 8, the implement 10 is adapted toergonomically support the crown portion 24 of the cranium of theintended user 12 when the latter performs a headstand. The configurationand size of the cranium receiving concavity 40 allows the latter to actas a socket for substantially fittingly receiving the crown portion ofthe cranium.

The combination of the dimensional characteristics of the implement 10and of the type of material chosen for forming the implement body 32allows the implement 10 to functionally accommodate a wide range ofcrown section configurations and sizes. Indeed, the selected dimensionalcharacteristics and degree of resiliency of the material synergisticallycombine to provide a tight fit to intended users having a wide range ofanthropometric characteristics.

The concavity main section 46 is configured and sized for contacting theportion of the cranium of the intended user 12 that would contact theground surface 36 if the implement 10 were not used and if the body ofthe intended user 12 was properly balanced along a substantiallyvertical axis 68. The concavity main section 46 is intended to providethat portion of the crown section of the intended user 12 with asomewhat more ductile or soft contacting surface than that of the groundsurface 36.

The concavity auxiliary section 48 is adapted to provide a greatercontact surface with the cranium of the intended user 12 then that whichwould have been in contact with the ground surface 36 should theimplement 10 had not be used and the intended user 12 has neverthelessbeen in a balanced vertical position. Hence, the contact surface withthe cranium is increased by the concavity auxiliary section 48.

The contact surface with the ground surface 36 is also increased by theimplement 10 since the body peripheral surface 62 tapers generallyinwardly in a direction leading from the ground contacting surface 34towards the concavity peripheral edge 54. The body peripheral surface 62is configured and sized for increasing the contact area of the craniumof the intended user 12 transmitted by the implement 10 to the groundsurface 36 without interfering with surrounding structures such as theforearms 20 of the intended user 12. Indeed, as shown in FIG. 7, theimplement 10 is configured and sized so as to leave a clearance betweenthe implement 10 and the forearms 20 of the intended user when thelatter uses the forearms 20 for additional support.

The radius of curvature of the concavity auxiliary section 48 allows thelatter to be angled relative to the ground surface 36 so as to provide areaction force against the weight of the intended user 12, the reactionforce having a horizontally extending vector segment so as to furtherhelp in stabilizing the intended user 12 in the proper position.Furthermore, as illustrated more specifically in FIG. 8, the resilientlydeformable nature of the body material from which the implement body 32is made is such that the implement body 32 is adapted to controllablydeform upon the axis 70 of the vertebral column 26 deviating from thevertical axis 68. This controlled deformation of the implement body 32protects the spine and, more specifically, the intervertebral discs bymitigating and taking up the bulging that would normally occur duringcompensatory adjustment as a result of body sway during the headstand.

Furthermore, the resilient nature of the body material from which theimplement body 32 is made is such that, upon deformation, the implementbody 32 will tend to resiliently spring back to its originalconfiguration hence creating self-aligning biasing forces that will tendto bias the vertebral column axis 70 towards the vertical axis 68 asindicated by arrow 72 in FIG. 8. These inherent self-aligning forces, inturn reduce the need for compensatory movement and/or forces emanatingfrom the user body that could potentially lead to injury.

In order to further increase the comfort associated with the use of theimplement 10, the resilient nature of the body material from which theimplement body 32 is made synergistically combines with the dimensionalcharacteristics of the concavity peripheral edge 54 taking intoconsideration other parameters from both the intended user 12 and theimplement 10.

The body minimal thickness 58 is also designed taking into considerationthe nature of the body material from which the implement body 32 is madeso as to prevent the head contacting surface 38 from contacting theground surface 36 and/or prevent the implement body 32 adjacent the headcontacting surface 38 from being compressed to the point of having amodulus of elasticity having a value over a predetermined threshold thatwould make use of the implement 10 uncomfortable.

Referring more specifically to FIG. 5, there is shown a headstandassisting implement in accordance with an alternative embodiment of theinvention generally indicated by the reference numeral 10′. Theimplement 10′ is substantially similar to the implement 10 and, hence,similar reference numerals will be used to denote similar components.

One of the main differences between the implements 10 and 10′ resides inthat at least part of the concavity main section 46 of the implement 10′is hollow. In other words, a central aperture 74 extends through theimplement body 32 in the region of the concavity main section 36.

Referring now more specifically to FIG. 6, there is shown a headstandassisting implement in accordance with a third embodiment of the presentinvention, generally indicated by the reference numeral 10″. Theimplement 10″ is substantially similar to the implements 10 and 10′ and,hence, similar reference numerals will be used to denote similarcomponents.

One of the main differences between the implement 10″ and the implements10 and 10′ resides in that at least part of the concavity main section46 and the concavity auxiliary section 48 are made out of differentmaterials. FIG. 6 illustrates a situation wherein an insert 76 made outof a different material is used. Preferably, at least part of theconcavity main section 46 is made out of a material having a lowermodulus elasticity than that from which the concavity auxiliary section48 is made.

Typically, at least the concavity main section is made out of a materialhaving a modulus elasticity having a value of approximately between 100and 400 kPA and at least part of the concavity auxiliary section 48 ismade out of a material having a modulus elasticity having a value ofapproximately between 10 and 40 kPA.

Typically, the modulus elasticity of the concavity main and auxiliarysections 46, 48 is substantially similar to or lower than thecorresponding modulus elasticity of the nucleus pulposus and annulusfibrosus of a physiologic intervertebral disc.

1. A headstand assisting implement for assisting an intended user whilesaid intended user performs a headstand, said intended user having ahead including a cranium, said headstand assisting implement comprising:an implement body, said implement body defining a ground contactingsurface for resting on a ground surface and a substantially opposedcranium contacting surface for contacting said cranium of said intendeduser; said cranium contacting surface being provided with a craniumreceiving concavity, said cranium receiving concavity being configuredand sized for substantially fittingly receiving a predetermined portionof said cranium of said intended user so as to ergonomically supportsaid cranium of said intended user when said intended user performs saidheadstand.
 2. A headstand assisting implement as recited in claim 1wherein said cranium receiving concavity has a substantially ovoidconfiguration when seen from a top view, said ovoid configuration ofsaid cranium receiving concavity defining a concavity long axisextending substantially longitudinally across said cranium receivingconcavity and a substantially perpendicular concavity short axisextending transversally across said cranium receiving concavity, saidconcavity long and short axes being sized so that the outline of saidcranium receiving concavity corresponds substantially to the outline ofsaid predetermined portion of said cranium of said intended user.
 3. Aheadstand assisting implement as recited in claim 2 wherein saidconcavity long axis has a value of approximately between 12.5 cm and 14cm and said concavity short axis has a value of approximately between 10cm and 11.2 cm.
 4. A headstand assisting implement as recited in claim 1wherein said cranium receiving concavity is configured and sized forsubstantially fittingly accommodating said predetermined portion of saidcranium of an intended user having anthropometric parameters locatedbetween that of the fifth and ninety fifth percentile of human craniums.5. A headstand assisting implement as recited in claim 2 wherein saidcranium receiving concavity has a substantially flattened parabolicconfiguration when seen in a longitudinal cross-section taken about saidoval long axis.
 6. A headstand assisting implement as recited in claim 1wherein said cranium receiving concavity defines a concavity mainsection and a concavity auxiliary section, said concavity main sectionbeing located substantially centrally relative to said cranium receivingconcavity; said concavity auxiliary section being located peripherallyrelative to said concavity main section, the radius of curvature of saidconcavity auxiliary section being greater then the radius of curvatureof said concavity main section.
 7. A headstand assisting implement asrecited in claim 6 wherein the concavity main section has a main sectionradius of curvature and the concavity auxiliary section has an auxiliarysection radius of curvature, the main section radius of curvature has avalue of approximately between 20 and 22 centimetres and the concavityauxiliary section radius of curvature has a value of approximatelybetween 3.6 and 5.1 centimetres.
 8. A headstand assisting implement asrecited in claim 6 wherein said concavity main section has asubstantially ovoid configuration, said ovoid configuration of saidconcavity main section defining a main section long axis extendingsubstantially longitudinally across said concavity main section and asubstantially perpendicular main section short axis extendingsubstantially transversally across said concavity main section.
 9. Aheadstand assisting implement as recited in claim 8 wherein said mainsection long axis has a value of approximately between 12.5 cm and 14 cmand said main section short axis has a value of approximately between 10cm and 11.2 cm.
 10. A headstand assisting implement as recited in claim6 wherein said concavity main section is hollow.
 11. A headstandassisting implement as recited in claim 6 wherein at least a portion ofsaid concavity main section and said concavity auxiliary section aremade out of different materials.
 12. A headstand assisting implement asrecited in claim 6 wherein at least a portion of said concavity mainsection is made out of a material having lower modulus of elasticitythen that from which said concavity auxiliary section is made.
 13. Aheadstand assisting implement as recited in claim 6 wherein at least aportion of said concavity main section is made out of a material havinga modulus of elasticity of approximately between 100 and 400 kPA and atleast a portion of said concavity auxiliary section is made out of amaterial having a modulus of elasticity of approximately between 10 and40 kPA.
 14. A headstand assisting implement as recited in claim 1wherein said cranium receiving concavity has a concavity peripheraledge, the level difference between said concavity peripheral edge andthe nadir of said cranium receiving concavity defining a concavitydepth, said concavity depth having a value of between 1.6 cm and 1.8 cm.15. A headstand assisting implement as recited in claim 1 wherein thedistance between the nadir of said cranium receiving concavity and saidground contacting surface defines a body minimal thickness, said bodyminimal thickness having a value of approximately between 0.635 cm and1.0 cm.
 16. A headstand assisting implement as recited in claim 1wherein said cranium receiving concavity has a concavity peripheraledge, said concavity peripheral edge having a substantially roundedconfiguration, the radius of curvature of said concavity peripheral edgehaving a value of approximately between 0.3 cm and 0.5 cm.
 17. Aheadstand assisting implement as recited in claim 1 wherein saidimplement body includes a body peripheral surface extending between saidconcavity peripheral edge and said ground contacting surface, said bodyperipheral surface tapering generally inwardly in a direction leadingfrom said ground contacting surface to said concavity peripheral edge.18. A headstand assisting implement as recited in claim 17 wherein saidbody peripheral surface extends at a peripheral-to-ground contactingsurface angle relative to said ground contacting surface, saidperipheral-to-ground contacting surface angle having a value ofapproximately between 65 degrees and 90 degrees.
 19. A headstandassisting implement as recited in claim 1 wherein said implement body ismade out of an integral piece of substantially resiliently deformablebody material.
 20. A headstand assisting implement as recited in claim19 wherein said body material is a urethane gel.